The present invention relates to a fish sonar which receives by a pair of stationary vibrators sound waves coming from any direction.
A sonar for receiving ultrasonic waves coming from any direction is conventionally known in which one vibrator is rotated by a scanning mechanism, and the receiving surface of the vibrator receives ultrasonic waves from this direction.
However, a conventional sonar of this type has been defective in that it requires a scanning mechanism for rotating the vibrator, so that the device becomes complex.
A sonar is also known in which a number of vibrators are arranged in an arc shape instead of rotating the single vibrator by a scanning mechanism. However, such a sonar has been defective in that the mechanism for rotating the respective vibrators becomes complex.
For improving the directional characteristics of the vibrator, the diameter of the vibrator is enlarged or a number of vibrators are used. However, when the diameter of the vibrator is enlarged, the directional characteristics cannot be improved since submaximum values are received. When a number of vibrators are used, the device becomes large, and adjustment procedures become complex.